The present invention relates to an air suspension, and more particularly to an improved air cell for an air spring.
A common air suspension system typically comprises a chassis of a vehicle and a longitudinal member extending generally lengthwise of the vehicle for pivoting about an axis generally transverse of the vehicle. The longitudinal member carries an axle having one or more road wheels. An air spring having a piston and an air cell is mounted spaced from the axis and acts as an adjustable compression spring between the vehicle and the longitudinal member to bias the wheels for effective road engagement and to buffer axle and wheel vibration.
Vehicles fitted with an air suspension are sometimes used without being inflated such as when being transported on railroad cars. At other times the vehicle axles are left to hang away from the chassis in an unloaded condition on the wheels such as when the vehicle is lifted on and off a ship. These operations cause the air spring to extend without air and pull away from the piston causing the air cell to “snap through” or invert. Once the air cell inverts, the air spring may have difficulty being correctly inflated. Further, if a load is again placed on the suspension while the air cell is inverted, the air spring is compressed and the air cell may become trapped between the piston and upper mounting resulting in damage to the air cell.
Accordingly, it is desirable to provide an improved air spring for a vehicle air suspension which minimizes the possibility of air cell inversion.